1. Field of the Invention
The present invention relates to improvements in supply funnel devices such as hoppers, conduits and related containers for dispensing and feeding solid particulate materials or powders such as toner compositions, meltextrusion compositions and similar finely-divided particulate compositions to a receptor container such as a toner cartridge or compartment, an extruder or any other empty, air-filled receptor container to be filled with the solid particulate composition.
2. State of the Art
It is recognized that the dispensing of finely-divided particulate compositions or powders from supply containers, through tapered or restricted spouts, into empty receptor containers results in the displacement of air from the empty receptor container and back-flow through the spout and into the supply container. This escape of air results in a counter-current of air against the flow of the solid particulate composition, which impedes throughput, negatively affects product quality, can create a safety concern (fire), reduces fill rate and work rate such as the extrusion rate. Moreover, fines or dust-size particles can become airborne and can pollute the atmosphere in the work area into which the displaced air is discharged.
Reference is made to U.S. Pat. 6,024,141 which discloses a fluidizing nozzle system for dispensing particulate powder compositions from a spiral auger such as toner compositions, which tend to be abrasive, easily charged and self-agglomerating so as to clog and resist flow. Dispensing is improved by providing the nozzle with a porous inner wall surface and force-feeding a supply of compressed gas into a plenum and through the nozzle wall to aerate and fluidize the toner composition, prevent sticking and agglomeration, and thereby facilitate flow into the receptor container. Preferably, the porous wall plenum also was an outlet which communicates with a vacuum source for eliminating positive pressure from the receptor container and removing stray airborne particulates.
Such systems are complex, involve the introduction of additional air into the particulate powder composition which can reduce the powder flow rate unless a spiral auger or other mechanical flow-inducer is used, and expose the receptor container to a vacuum pressure which can withdraw excessive amounts of the fluidized powder composition at the mouth of the receptor container.
Reference is also made to my U.S. Pat. No. 5,221,945 which discloses a toner cartridge having a closed supply compartment for feeding toner powder to a hopper when a floor seal is peeled away to open the compartment to the hopper. A passageway is provided through the toner powder to permit air, which becomes displaced from the hopper, to flow back into the closed toner compartment, above the level of the toner powder. This prevents the displaced air from impeding the flow of the toner powder and equalizes the air pressure within the supply compartment.
While such toner cartridges are effective for their intended purposes, they are restricted to the feeding of toner powder from a closed supply container having a retractable floor slide which first opens the air passageway to the receptor hopper and then opens the supply container for the gravity flow of toner powder. Such systems are not useful for the continuous large batch supply of particulate compositions, such as extrusion compositions, from a continuously fed supply hopper. Moreover, the area of air-relief is localized at one side of the particulate flow causing the path of some of the escaping air to intersect the path of the particulate flow, resulting in turbulence and aeration and escape of some of the smaller particulates with the escaping air.